Apparatus for sensing gearbox shifting positions

ABSTRACT

The invention relates town apparatus for connection to a gearbox actuating element of an engine gearbox, having sensors ( 5, 6, 7 ) for sensing gearbox shifting positions of a shifting apparatus, and to an interface ( 2 ) for transferring the evaluation signals of the sensors ( 5, 6, 7 ) to the control electronics of a gearbox actuating element, wherein the sensors ( 5, 6, 7 ) are arranged in such a way that their spacing from the interface ( 2 ) is smaller than the spacing between the interface ( 2 ) and the shifting apparatus which is to be sensed.

The invention relates to an apparatus for sensing transmission shifting positions, in particular to a sensor module for making available sensor signals for a transmission actuator.

Electronically controlled transmissions of motor vehicles are set by means of transmission actuators which receive electronic control signals and convert them into mechanical actuating positions. In this context, a plurality of actuators, usually pneumatically driven actuating pistons, are used for the gear speed, gate, split and range. In order to determine the travel position of an actuating piston which is used for one of the abovementioned functions, position sensors or travel sensors are used which specify the current position of the piston to an electronic evaluation unit. In this way, a control circuit is provided which receives a specific transmission position as a set point value and sets the transmission in accordance with the input signal.

Typical sensors which are used for this purpose are what are referred to as PLCD travel sensors (permanent magnetic-linear-contactless-displacement sensors). These known sensors are essentially composed of a soft magnetic core which is surrounded by a coil. A permanent magnet which is moved toward the sensor leads to a virtual division of the core. If a suitable alternating current is applied to the primary coil, a voltage which is dependent on the position of the permanent magnet is induced in the evaluation coils. The sensor is supplied with a suitable alternating current and the signals are processed, evaluated and converted by electronics which are specially provided for this purpose.

Disadvantages of the known devices for setting a transmission are the complex spatial configuration and the connection equipment for connecting the electronic evaluation unit and the sensors to the electronic control unit. The long lines and the fact that the sensors are distributed over long distances entails an increased level of susceptibility to faults. Furthermore, mounting is costly and expensive.

An object of the present invention is to make available an apparatus of the type mentioned at the beginning which permits simplified mounting and is less susceptible to faults.

The object is achieved according to the invention by means of a device for connection to a transmission actuator of an engine transmission, which device comprises sensors for sensing transmission shifting positions and an interface for transmitting the evaluation signals of the sensors to the electronic control unit of the transmission actuator. According to one advantageous aspect of the present invention, the sensors are arranged here in such a way that the spatial distance from the common interface is shorter than the distance between the interface and an actuating device to be sensed. The actuating device can advantageously be a transmission or a transmission actuator, and in particular the actuating pistons of a transmission actuator. According to this embodiment, the sensors are no longer distributed and are arranged as closely as possible to the transmission or to the actuating piston of the transmission actuator in order to determine the travel positions there. Instead, the present invention proposes that the sensors be advantageously arranged in as compact a fashion as possible between the objects to be sensed, for example the actuating pistons of the transmission actuator or the transmission and the interface, in order to transmit the evaluation signals. The invention provides that the device be arranged directly on the transmission, for example for the actuating pistons of a transmission actuator or in order to sense the transmission shifting positions of a transmission. The interface is embodied as a single common interface for all the sensors. This makes it possible to position the sensors and the interface closely to one another in a spatially compact arrangement. The evaluation signals of the sensors can accordingly be connected directly via the common, and therefore also single, interface of the device according to the invention to the further electronic control unit for the transmission actuator or the engine. This makes a very space-saving and simple design of the device according to the invention possible. It is therefore not necessary to provide any cable connections which are long and susceptible to faults between the sensors and the further electronics. Instead, very short connections are possible between the interface and the sensors. The mounting and the replacement of a device according to the invention can additionally be simplified as a result of the arrangement of the sensors according to the invention by virtue of the fact that the device is configured as a compact modular unit. As a result, the device according to the invention can be arranged in the form of a sensor module at a position on the transmission actuator with a small number of manual maneuvers. This aspect is additionally improved if the common interface is formed, in a way which is advantageous in terms of space, by a multiplicity of metallic connections, for example a standardized interface. According to the invention, a plug or a further module is coupled to said interface in order to be able to use the evaluation signals of the sensors to control the transmission.

According to a further advantageous aspect of the invention, the sensors are used to sense the gear speed position, the gate position and the split position of the transmission. In this context, account is taken in particular of the fact that with conventional solutions these three actuating functions of the transmission actuator cause the sensors to be distributed widely over the transmission actuator or the transmission. The invention now proposes that instead a modular compact unit, in which the sensors for all the actuating pistons are located, be provided for three different actuating positions such as gear speed, gate and split. This is successful only if the sensors are provided skillfully on the actuating pistons with respect to the signal transmitters, in such a way that the compact modular form can be achieved. Signal transmitters may be, for example, small permanent magnets, but they may also be coils or other elements which, as a result of the change in their position, bring about a change in electrical, magnetic or other fields, the change in which is detected by the sensors of the device according to the invention. For this reason, according to one advantageous aspect of the present invention, the signal transmitters for the sensors are arranged on the actuating pistons of the transmission actuator or on the transmission in such a way that the inventive compact design of the device with the sensors is made possible.

According to a further advantageous aspect of the present invention, the sensors will assume essentially the same distance from the actuating pistons which are to be sensed and whose travel position is to be respectively picked up by a sensor. This is ensured by virtue of the fact that there is an optimum region in which all three sensors can be arranged. If this is taken into account, the sensors can be accommodated in a compact housing, with the result that a modular design of the device according to the invention is made possible.

According to a further advantageous aspect of the invention, the sensors are arranged in such a way that their longitudinal axes are essentially perpendicular to one another. A number of advantages are therefore achieved at the same time. Since according to the invention the sensors are arranged relatively close to one another, there is a certain risk of the signals of the actuating pistons influencing one another reciprocally in such a way that the sensors of the respective other actuating pistons also receive a signal of an actuating piston which is not assigned to them, for example in attenuated form. This aspect of the present invention is based on the idea that the travel position of the actuating pistons is determined by the sensors by means of electromagnetic waves by inductive or capacitive coupling. As a result, coils which detect a change in internal or external magnetic fields are used in the sensors. When sensors are arranged closely to one another, this can lead to the abovementioned interference. Such interference can be reduced or eliminated if as far as possible the sensors are all arranged perpendicular to one another in pairs. Although a certain reduction in the undesired mutual influencing can be brought about if the distances between the sensors are made sufficiently large, this cannot always be ensured to a sufficient degree when there is a very compact design in the spatially restricted conditions on a transmission or transmission actuator.

However, the invention is in fact aimed at achieving a compact design. For this reason it is proposed that instead the sensors be each arranged perpendicularly to one another in pairs. This permits a particularly compact arrangement in a common housing with reduced mutual influencing.

According to a further advantageous embodiment of the invention, the respective electronic evaluation unit for the sensors are likewise arranged between the transmission or the actuating pistons of the transmission actuator and the common interface of the sensors. According to a further advantageous embodiment, the electronic evaluation unit is even advantageously located between the respective sensors and the interface. This also permits a very effective and compact design of the device according to the invention as a module. It can be advantageously provided in this case that the electronic evaluation unit is embodied as a compact unit for a plurality of sensors or as a compact unit for each sensor. As a result, the connecting lines between the sensors and the electronic evaluation unit are kept very short, which in turn reduces the susceptibility to interference and faults.

The invention advantageously also provides that the sensors be embodied as PLCD sensors. This also ensures a spatially small and compact arrangement within the device according to the invention. In particular with respect to PLCD sensors, the paired, perpendicular arrangement of the sensors with respect to one another is advantageous since these sensors are based on a determination of the transmission shifting position of a transmission or the travel position of an actuating piston by means of a signal transmitter (permanent magnet). The coupling between the sensor and signal transmitter is, as in the case of most electromagnetic couplings, directional and spatially limited. Both the spatial proximity between the sensor and the signal transmitter and their orientation with respect to one another is significant. Sensors which are arranged perpendicularly with respect to one another reduce the negative mutual influencing between sensors which are arranged close to one another.

According to a further aspect of the present invention, the signal transmitters for the respective sensors are arranged on the actuating pistons in such a way that the sensors can be arranged in pairs perpendicularly to one another between the actuating pistons and the common interface. This advantageously ensures that the interaction of the signal transmitters between the respectively assigned sensor is maximized and the interaction between the signal transmitters between the other sensors is minimized.

It is also advantageous if the common interface is embodied as a standardized interface, in particular as a connection according to standard IP6K9K. Said interface is protected against the ingress of dirt, water etc. Standardized interfaces are generally available and can be connected to a large number of different embodiments of transmission actuators. Furthermore, they are spatially compact and can be connected by means of simple manual maneuvers to the elements to be coupled on the transmission actuator or to some other electronics.

An exemplary embodiment of the present invention will be described by way of example with reference to the following figures, of which:

FIG. 1 shows a sensor module according to the invention in a perspective view,

FIG. 2 shows the exemplary embodiment according to FIG. 1 in a perspective, semi-transparent illustration, and

FIG. 3 shows the exemplary embodiment according to FIGS. 1 and 2 in a further perspective illustration with highlighted components.

FIG. 1 shows an exemplary embodiment of the sensor module according to the invention. The sensor module 1 according to the invention is surrounded by an enclosed housing 4. A first interface 2 and a second interface 3 stand out from the housing. The first interface 2 has internal rows 13 of metallic contacts. These contacts conduct the signals of sensors (not illustrated) which are accommodated in the sensor module 1, and the signals of a second interface 3 to the electronic control unit (ECU). The second interface 3 also has a row of contacts. The first interface 2 can advantageously be embodied as a plug-type connection according to the IP6K9K standard. However, other embodiments are also conceivable provided that the interface can be coupled to an electronic control unit of a transmission actuator. The electronic control unit for the transmission actuator must therefore have an interface which corresponds to the first interface 2. In one advantageous embodiment, further control units are also received by means of the first interface 2 from an electronic control unit (not illustrated in FIG. 1) for the transmission actuator, and are passed through the interior of the sensor module 1 to a further (second) interface 3. Electronics can be provided in the sensor module 1 in order to perform further processing of these additional, passed-through signals. In one advantageous embodiment, the signals are, however, connected through to the second internal interface 3 without further processing. These signals may advantageously be signals for actuating electromagnets for the transmission actuator. So that only a single external interface 2 with the outside is formed, the additional lines or signals for the second internal interface 3 are conducted internally through the external interface 2. The housing of the device according to the invention is configured in such a way that it can be inserted in an optimum, space-saving way into a restricted space on the transmission actuator or even on a transmission.

FIG. 2 shows the exemplary embodiment of a sensor module according to the invention as in FIG. 1 in a semi-transparent illustration in which the enclosed housing is indicated only in the form of dashes. This method of illustration permits the components arranged in the sensor module to be seen. These are sensors 5, 6, 7 for determining a transmission shifting position, for example of cylinders of a transmission or actuating pistons (not illustrated) which sensors 5, 6, 7 sense the actuating measures of the transmission actuator either directly on the actuating pistons or on the transmission. In the exemplary embodiment illustrated in FIG. 2, electronic evaluation units 9, 14, 8 are provided for each sensor 5, 6, 7. The division into three individual components for the electronic evaluation unit is, however, not compulsory. Likewise, a single electronic evaluation unit can be used for all the sensors 5, 6, 7. The signals are fed from the electronic evaluation unit to the interface 2 via connecting lines. The sensors 5, 6, 7 are connected to the evaluation electronic unit via various connecting lines. The components of the evaluation electronic unit 9, 14, 8 are connected to the interface 2. The second interface 3, which makes available signals which are received by the external, first interface 2, makes available a series of further electrical contacts, for example for actuating magnets for controlling the pneumatic gates, gear speed and split pistons. The sensors 5, 6, 7 are embodied as a first sensor 5, second sensor 6 and third sensor 7 in a specific arrangement. The sensors 5, 6, 7 may be PLCD sensors. These sensors 5, 6, 7 are provided for sensing the position of each actuating piston of the transmission actuator. This is done, for example, by inductive coupling. In one embodiment as a PLCD sensor, magnets, whose movement brings about a corresponding signal in the PLCD sensors, are arranged as signal transmitters on each component to be sensed, for example on the actuating pistons or at a suitable position on the transmission. This signal is converted in a suitable way by the electronic evaluation unit 9, 14, 18 in order for it to be passed on via the first interface 2 to the electronic control unit of the transmission actuator. In one advantageous embodiment, the external interface may be designed to communicate with a specific bus system.

FIG. 3 is a further illustration of the exemplary embodiment according to one aspect of the invention, which illustration permits an even deeper view into a sensor module according to the invention. Here, the electronic evaluation unit 8 and the first interface 2 are now also illustrated in the transparent way, that is to say with dashed lines, and the closed housing is completely removed. As a result, it is possible to see the sensor 7, which extends in a direction of the sensor module, in a similar way to the sensors 5 and 6. The connecting lines 10, 11, 12 connect the sensors 5, 6, 7 and their respective electronic evaluation unit 9, 14, 18. The electronic evaluation unit 8, 9, 14 transmits the evaluated signals via the connecting lines 15, 16, 17 and the interface. The evaluation signals of the sensors are transmitted to the electronic evaluation unit 9, 14, 8 via the connecting lines 10, 11, 12.

In the illustration according to FIG. 3 it is also clear that the sensors are arranged paired perpendicular to one another. This arrangement specifies how the signal transmitters have to be arranged on the transmission or on the actuating pistons or cylinders of the transmission actuator. An advantage of such an arrangement is that the signals of the signal transmitters on the actuating pistons or in the transmission have a weaker influence on one another. However, the paired perpendicular arrangement is just one of a number of possibilities. The mutual interference of the signal transmitters or of the sensor signals can also be limited by means of a sufficient distance between the sensors or signal transmitters. The division of the electronic evaluation system into three individual components 9, 14 and 8 is also illustrated but it is not compulsory. It is decisive that the electronic units 9, 14, 8 and the sensors 5, 6, 7 are located between the actuating pistons or the transmission and the interface 2. This permits a very compact design to be obtained. The inventive sensor module in accordance with the exemplary embodiment described above therefore constitutes the universal interface between the actuators and the sensors 5, 6, 7 which are necessary to operate a transmission actuator. Most of the control signals and sensor signals are advantageously conducted through the first interface 2 here. As a result, the expenditure on plugs is reduced compared to the prior art. A lower number of plug-type connections reduces the risk of the ingress of dirt and of other undesired interfering influences. Overall, the system's susceptibility to faults is also reduced by decreasing the number of external interfaces. The expenditure on mounting is also reduced. 

1. Apparatus for connection to a transmission actuator of an engine transmission, characterized in that the device comprises sensors (5, 6, 7) for sensing transmission shifting positions of a shifting device and an interface (2) for transmitting the evaluation signals of the sensors (5, 6, 7) to the electronic control unit of a transmission actuator, wherein the sensors (5, 6, 7) are arranged in such a way that their distance from the interface (2) is shorter than the distance between the interface (2) and the shifting device to be sensed.
 2. The apparatus as claimed in claim 1, characterized in that the shifting device to be sensed comprises the actuating pistons of a transmission actuator.
 3. The apparatus as claimed in claim 1, characterized in that the shifting device to be sensed comprises a transmission whose transmission shifting positions are sensed.
 4. The apparatus as claimed in claim 1, characterized in that sensors (5, 6, 7) are provided for sensing the gear speed position, the gate position and the split position.
 5. The apparatus as claimed in claim 1 or 2, characterized in that the sensors (5, 6, 7) are arranged in such a way that the distance between the sensors (5, 6, 7) and the corresponding actuating pistons, to be sensed, of the transmission actuator, are essentially equal in size.
 6. The apparatus as claimed in one of the preceding claims, characterized in that the sensors (5, 6, 7) are arranged in such a way that their longitudinal axes are essentially perpendicular to one another.
 7. The apparatus as claimed in one of the preceding claims, characterized in that the electronic evaluation unit (8, 9, 14) for the sensors is arranged in a compact design between the actuating pistons and the common interface of the sensors.
 8. The apparatus as claimed in one of the preceding claims, characterized in that the sensors (5, 6, 7) are PLCD sensors.
 9. The apparatus as claimed in one of the preceding claims, characterized in that the interface (2) is a plug-type connection according to the IP6K9K standard.
 10. The apparatus as claimed in one of the preceding claims, characterized in that a second interface (3) is provided which makes available signals which are received by the external, first interface (2). 